Spherical tank



Sept 23, 1947. e T. HORTON 2,427,676

SPHERICAL TANK Filed March 1, 1945 2 Sheets-Sheet 1 M fimlldlliL GeorgeW 2 ZMM fi/ r/ V I III? lillfl n I II I. v

p 1947- s. T. HORTON 2,427,676

SPHERICAL TANK v Filed March 1, 1945 2 Sheets-Sheet 2 a II I Wm iPatented Sept. 23, 2947 srnnarcar. TANK George T. Horton, Chicago, 111.,assignor to Chlcago Bridge to Iron Company, a corporation of IllinoisApplication March 1, 1945, Serial No. 580,428

9 Claims. (01. 220-1) This invention relates to elevated tanks for thestorage of fluids, and relates particularly to a spherical tanksupported on circumferentiallyspaced columns.

It has been found in the past that elevated tanks, and especiallyspherical tanks, are subjectedto expansion and contraction caused by theheat of the sun, changes in temperature caused by the weather,variations in pressure, and the like. These expansions and contractionssometimes tear the tank loose from its supporting legs or columns andthus many of these tanks require frequent and expensive repairs. Theyare especially bothersome with spherical tanks as it is difiicult toattach supporting columns to the tank, this being usually done bywelding the columns to the sides of the tank at points below thehorizontal equator. As the columns are welded to the tank at an angle,any loosening of the welding by expansion or contraction immediatelybrings the weight of the tank to bear on the weakened portion and tendsto tear the whole column loose. A tank so supported tends to rock backand forth and this fact increases the problem of providing adequatesupport for the spherical tank.

I have discovered how spherical tanks can be constructed so that theforces of expansion and contractions of the tank are nullified and donot afiect the weld between the supporting column and the tank. I havealso discovered a simple way of bracing the tank so as to prevent itfrom rocking about any axis. I accomplish these results by providingcolumnar supports which are attached to the spherical tank so that whenthe tank expands and contracts, the column at the, point of attachmentwill also expand and contract. I also provide tie rods at the bottom ofthe tank running to certain of the columns in order to brace the tankagainst any rocking action. For greater stability, these tierods arearranged substantially in the form of an equilateral triangle.

The invention will be described in detail as related to the embodimentof the same set out in the accompanying drawings. Of the drawings,Figure 1 is an elevation of a spherical tank built according to theprinciple of this invention; Figure 2 is a plan view of the sphericaltank of Figure 1 with tie rods shown in dotted lines; Figure 3 is avertical section taken along line 33 of Figure 1; and Figure 4 is ahorizontal section taken along line 4-4 of Figure 3.

In the embodiment shown in the accompanying drawings, a spherical tank Iis supported on a plurality of circumferentially-spaced vertical columnsll. At the bottom of certain columns are provided angular tie rods i2extending from said columns to the bottom portion of the spherical tankIll. These tie rods are in the form of a Substantially 60 angle with acolumn in the angular poration and the two ends of the rods attached, asby welding. There are provided three of these tie rods and an end of oneis substantially aligned and overlapping with the end of another. Theyare arranged so that when viewed from above they form a substantiallyequilateral triangle as shown in Figure 2.

Each of the supporting columns is of a hollow construction and isattached to the tank at the top end I! at a position beneath thehorizontal equator oi the tank. Where the column contacts the tank thereis a cut-out portion out along a surface having the same shape andcurvature as the corresponding portion of the spherical tank. Thiscutout portion ordinarily will not exceed substantially two-thirds ofthe diameter of the column. The resulting edges of the cutout portionare attached to the tank by welding. On

top of each column there is provided a rounded cap i4 having asphere-contacting edge portion of the same curvature as said spheres andattached to the column and to the sphere by welding. The proportions ofthe cutout portion are of course such as to secure proper balance. Thedepth of the cut is also such as to provide adequate surface andflexibility.

Within each column ll there is proportioned one or more flat angulardiscs l5 to reinforce the column.

At the bottom of each of three equally spaced columns there is providedan angular tie rod [2. These angular rods form substantially a angle andare positioned with one of the columns in the angle and with the twolegs of the rods welded to the bottom of the tank. The end of one tierod is aligned with and overlapped by an end of another rod. This givesthe tie rod assembly the appearance of an equilateral triangle whenviewed from above, as is shown in Figure 2. Such a triangulararrangement gives greater stability to the structure and prevents thesphere from rocking.

As the top ends of the columns are attached to the sphere in a cut outportion, as explained hereinabove. and the resulting edges only of thecolumns are welded to the sphere, thecontacting portion of the column isable to expand or contract by spreading when the sphere expands orcontracts. Thus the welded portion is placed under no excessive strainand there is no tendency for the column to tear loose from the sphere.This has a decided advantage over the prior methods of building suchspherical tanks as it reduces repair work on the sphere supportingstructures to a It is, of course, apparent that in order for the columnto flex with the expansion and contraction of the spherical tank it isnecessary that the column be made of a flexible steel and not somematerial like cast iron, or the like, that is inflexible.

This method of attaching supporting columns to spherical tanks has stillanother advantage in that it permits the top of each column to bend andthus adapt itself to transverse forces such as wind blowing against theside of the tank which tend to shift the position of the tank. Thus theinvention allows the columns to give with forces exerted in and on thetank and prevents the columns from being torn loose by these forces.

Having described my invention as related to a typical embodiment of thesame, it is my intention that the invention be not limited to any of thedescriptive details, unless otherwise specified, but rather be construedbroadly within its spirit and scope as set out in the accompanyingclaims.

I claim:

1. A spherical storage tank comprising a hollow sphere and a pluralityof circumferentiallyspaced tubular columns supporting said sphere, eachof said columns contacting the sphere at an area near the top of thecolumn and cut out in a surface having the shape of the correspondingsection of the sphere and welded at the resulting edges to said sphere,and each of said columns having a rounded closed top portion with asphere-contacting edge welded to the sphere, with all the weldedsphere-contacting edges being substantially continuous.

2. A spherical storage tank as set out in claim 1 wherein each of saidcolumns has its top portion beneath the horizontal equator of saidsphere.

3. A spherical storage tank as set out in claim 1 wherein three angulartie rods are provided each extending from a column to the sphere witheach of said rods having a column in the angle and the two legs of therod being welded to the sphere at the bottom of the sphere, said tierods being arranged so that the end of a leg of one substantiallyoverlaps the end of a leg of another and all three tie rods formsubstantially an equilateral triangle when viewed from above.

4. A spherical storage tank comprising a hollow sphere, a plurality ofcircumferentially-spaced tubular columns supporting said sphere, witheach of said columns contacting the sphere at an area near the top ofthe column and being cut out in a surface having the shape of thecorresponding section of the sphere and welded at the resulting edges tosaid sphere, and a rounded cap at the top of each column with each caphaving a sphere-contacting edge portion of substantially the samecurvature as said sphere and with each cap attached to the sphere and tothe column as by welding, the sphere-contacting edge of said cap beingsubstantially a continuation of the sphere-contacting edge of itscolumn.

5. A spherical storage tank as set out in claim 4 wherein angular tierods are provided extending from certain columns to the sphere with eachof said rods having a column in the angle and the two legs of the rodbeing attached to the sphere.

6. A spherical storage tank as set out in claim 4 wherein angular tierods are provided extending from certain columns to the sphere with eachof said rods having a column in the angle and the two legs of the rodbeing welded to the sphere at the bottom of the sphere.

7. A spherical storage tank as set out in claim 4 wherein said cutoutportions of each column do not exceed in maximum depth a distancesubstantially equal to two-thirds of the diameter of said column.

8. A spherical storage tank comprising a hollow sphere and a pluralityof circumferentially-spaced tubular columns supporting said sphere, eachof said columns contacting the sphere at an area beneath the horizontalequator of the sphere and near the top of the column and each columnbeing cut out in a surface having the shape of the corresponding sectionof the sphere and welded at the resulting edges to said sphere, saidcolumns each being capped at the top with a rounded cap having asphere-contacting edge portion of the same curvature as said sphere andbeing ttached to the column and to the sphere as by welding, thesphere-contacting edge of said cap being substantially a continuation ofthe contacting edge of its column.

9. A spherical storage tank comprising a hollow sphere and a supportingstructure, said supporting structure comprising a plurality ofcircumferentially-spaced tubular columns attached to the sphere at areasbeneath the horizontal equator of the sphere and near the tops of thecolumns and each column being cut out in a surface having the shape ofthe corresponding section of the sphere to a depth not greater than thediameter of said tubular column and welded at the resulting edges tosaid sphere, said columns each being capped at the top with a roundedcap having a sphere-contacting edge portion of the same curvature assaid sphere and being attached to the column and to the sphere as bywelding, and three angular tie rods each extending from a column to thesphere and having a column in the angle with the two legs of the rodbeing welded to the sphere at the bottom thereof, said tie rods beingarranged so that the end of a leg of one substantially overlaps the endof a leg of another and all three tie rods form substantially anequilateral triangle when viewed from above.

GEORGE T. HORTON,

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date D. 125,769 Horton Mar. 11, 19411,997,808 Blackburn Apr. 16, 1935 1,953,949 Boardman Apr. 10, 19342,156,400 Pechstein May 2, 1939 1,517,006 Horton Nov. 25, 1924

